The Things Network is a global, crowdsourced, open, free and  decentralized internet of things network for enabling data connectivity  across diverse applications. The network allows ultra-low power things  (nodes) connect to the internet for seamless data exchange across  several platforms. The Network makes use of LoRaWAN technology. LoRaWAN,  is a Low Power Wide Area Network (LPWAN), is used to transport  telemetry data over an extended range of up to several kilometers.
A node, named a “Thing” in the network connects to a gateway to publish telemetry data to a server on the internet, which can then exchange data between multiple internet services.

How to Get Started
Building an application: The Things Network is an open source, decentralized infrastructure for the Internet of Things. The community edition is free for fair use. Getting started with an IoT application is easy.
The Things network has “The Things Node” and “The Things Uno”, with which you can get started in no time. Don’t worry you can also use any certified LoRaWAN device. Things Network has built an Arduino SDK which enables sending messages in just a couple of lines.
The Things Node and The Things Uno use the arduino platform and the Microchip RN modules.
: Gateways are the bridge between devices and The Things Network. In most cases, it is a packet forwarder with LoRa concentrators, that can receive and transmit LoRa packets.
Since LoRaWAN operates on License free bands, one can quickly setup a TTN gateway. Setting up a gateway is entirely legal, however, there can be local or regional restrictions of some kind. You can go through different supported gateway hardware on the page.

Community, You are the Network
The Things Network has a strong and active community around the world. People around the globe discuss ideas, use cases, help each other and contribute. You can start a community anywhere, and be an initiator.
The core principles of The Things Network community are:
Endorsing the principles mentioned in the Manifest of The Things Network.
Open for anyone.
People are the foundation of the community, not gateways.
Regular social contact is the driving force of the community’s development.
Diversity is crucial.
Till date [24/04/2018] India has 10 communities and 17 gateways (Things Network India).